CVE-2026-76844

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.59% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 48.0% of scored records. A rank, not a probability.

NVD base score

8.3 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD analysis status

Deferred. NVD last modified this record on 2026-10-12.

Red Hat severity

Important. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-08-24 13:12Z2 MO AGO

Last updated

2026-10-01 11:03Z27 DAYS AGO

Reserved

2026-08-19

Assigning CNA

VulnCheck

Record state

PUBLISHED

Severity

High (CVSS 8.3)

CNA CVSS vector

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

Weaknesses

• CWE-787Out-of-bounds WriteBase
• CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')Base

Data version

5.2

Document digest

2118510ec4f83919d22f05c7e4d622a4db983bd55ea5d57aa7924c42074e169a

• gist.github.comTechnical report and proof of concepthttps://gist.github.com/thesmartshadow/e0b9481792afb7c31e86fee1ff084490technical-descriptionexploit
• github.comPatch Commithttps://github.com/madler/zlib/commit/df84af25dc1942490e1d1c899a07619152a46148patch
• github.comhttps://github.com/madler/zlib/blob/v1.3.2/gzwrite.c#L393technical-description
• github.comhttps://github.com/madler/zlibproduct
• www.vulncheck.comVulnCheck Advisory: zlib 1.3.1.2 through 1.3.2 Heap Buffer Overflow via gz_vacatehttps://www.vulncheck.com/advisories/zlib-1.3.1.2-through-1.3.2-heap-buffer-overflow-via-gz-vacatethird-party-advisory